12 CHEMICAL STATICS 



the same composition, e. g. silver chloride always contains 

 75.26 VAg. 



2. The law of multiple proportions, according to which 

 two elements that come together in several compounds 

 occur in the same ratio, or in ratios that are related by 

 means of w T hole numbers ; e. g. compare 



Silver chloride (with 24-74 % Cl and 75-26 / o Ag) and 

 Silver chlorate (with 18-54 % 01 and 56.40 % Ag) ; 

 the ratio of chlorine to silver is the same in the two, 

 viz.: 



24-74 : 75-26 = 0-329 and 18-54:56-40 = 0-329. 

 On the other hand, compare 



Chlorine iodide (21-84 % Cl and 78-16 % iodine) and 

 Chlorine tri-iodide (8-52 % Cl and 91-48 / o iodine); 

 the two ratios of chlorine to iodine are in a whole number 

 proportion, for 



21-84 : 78-16 = 0-279 and 8-52 : 91-48 = 0-093 = ^x0-279. 



3. The law of equivalents, which expresses that two 

 elements combine with equal quantities of a third, in 

 a ratio equal to that in which they combine with one 

 another, or in a ratio related to the latter by a whole 

 number. If, e. g., we compare 



Silver chloride (24-74% Cl and 75-26 % Ag), 

 Silver iodide (54-04 % I and 45-96 % Ag), with 

 Chlorine iodide (21-84% Cl and 78-16 % I), 

 the ratio of the amounts of the elements combined with 

 equal amounts say 75-26 parts of silver is : 



24-74 : 54-04 x |^ = 0-279, 



i.e. the same as in the direct combination of chlorine 

 and iodine. 



If we had chosen chlorine tri-iodide (with ratio 0-093) 

 as instance, then obviously the integral ratio 3 : 1 would 

 have been found. 



